Children as young as 12 are using an arsenal of deadly weapons by joining some of Liverpool's most dangerous gangs, an investigation has revealed.

Tripod-mounted machine guns, 9mm pistols, pump-action shotguns and revolvers are among weapons being used by teenagers vying to dominate the city's toughest estates, a BBC Panorama programme will disclose tomorrow. Many gang members video their weapons on mobile phones, mix the footage into short films and post them on the internet with music from rappers such as Biggie Smalls, the American singer who was shot dead in 1997. The videos are used to show off and to cement gang identity but also to act as a deterrent by showcasing hidden armouries to rival gangs.

In the programme, John, 14, says he has been involved in 30 firearms incidents, including shooting at rival members, being shot at and 'spraying up' houses with machine guns. In his mother's kitchen, he describes the cleaning-up ritual he goes through each time he fires a gun, in order to beat police DNA and forensic tests.

It involves burning some of his 'Lowies' - the gangs' all-black uniform of Lowe Alpine, Berghaus and North Face trekking gear - and 'petrolising' his hands and body to wash away particles of gunpowder. John was part of the Moss Edz gang, based in the Page Moss district of Huyton, led by Lee, also 14.

Lee's father, who is separated from his mother, warned that the violence would not stop. 'They are not afraid to die, they are what they are, it's not going to end. It's not our area, it's not the adults' area any more, it's the kids' area.'